Bulgarian fishermen have found an ancient fishing boat in the Gulf of Sozopol on November 28, Dnevnik daily reported. The boat was found during a routine fishing trip and was taken to Sozopol's archaeological museum.

Apparently made of oak wood, the boat was built using metal tools, which made it unlikely to be dating back to pre-historic times, the museum curator Dimitar Nedev said.

About 70cm wide, 60cm tall and 1.2m long, the age of the boat was initially dated as between the Roman period and the fourth century CE, which would make it one of the oldest surviving boats in history.

The explanation, according to Dnevnik, is that the high amount of hydrogen sulfide in the Black Sea prevents timber decay. When taken into the air, rapid oxidation can destroy the timber, but the fishermen had prevented the process by filling the boat with sea water.